Targeting Parasitic DHFR: Montclair State Students Advance Antifolate Drug Discovery for Lymphatic Filariasis

At the 2025 Theobald Smith Society Spring Symposium, graduate students David Otu-Aboagye and Salma Kwarteng from Nina Goodey’s Lab at Montclair State University presented an engaging talk on their research into novel drug targets for lymphatic filariasis—a neglected tropical disease that affects hundreds of millions globally.

The parasite responsible for most cases of lymphatic filariasis is Wuchereria bancrofti, a mosquito-transmitted nematode that causes severe swelling of limbs and tissue (elephantiasis) by invading the lymphatic system. Despite its enormous global health burden, treatment remains reliant on long-term preventive chemotherapy, which has significant compliance and efficacy challenges.

Otu-Aboagye and Kwarteng’s research focuses on W. bancrofti dihydrofolate reductase (Wb DHFR), an essential enzyme for DNA synthesis and cell division, and a known drug target in other organisms. The goal is to identify antifolate compounds that selectively inhibit Wb DHFR without affecting the human version of the enzyme.

The team expressed a His₆-tagged Wb DHFR construct in E. coli LOBSTR cells, optimized for purifying histidine-tagged proteins. Following IPTG induction, they used a two-step purification process—first with methotrexate-agarose resin, then with Ni-NTA affinity chromatography. Protein yield and purity were confirmed via Nanodrop and Bradford assays.

Kwarteng described their use of sitting-drop vapor diffusion to crystallize the purified enzyme for structural studies. Crystals were grown using tri-sodium citrate, PEG 4000, and ammonium sulfate, then analyzed via X-ray diffraction at Brookhaven National Laboratory. The team also tested a series of methotrexate-like compounds (TSD001, TSD025, and TSD010) for their ability to inhibit Wb DHFR.

Methotrexate, while a potent DHFR inhibitor, is unsuitable for treatment because it also inhibits human DHFR. Of the three TSD compounds, TSD001 emerged as the most promising candidate, showing the lowest IC₅₀ and strongest binding affinity. Structural analysis revealed key interactions at arginine 72 and isoleucine 10 within the enzyme’s active site—interactions absent in the weaker inhibitor TSD010 due to steric hindrance caused by a methoxy group.

The students plan to further optimize these compounds for selectivity and test them against human DHFR to evaluate off-target effects. Their project exemplifies the intersection of structural biology, medicinal chemistry, and global health research—work that may one day contribute to safer and more effective treatments for a devastating parasitic disease.

Check out David and Salma’s talk: https://youtu.be/ZucpL9G4ftA